NEW YORK (Reuters Health)
— Older men considering taking testosterone for low libido,
fatigue, irritability or muscle loss should be made aware of the
heart-related risks of testosterone therapy, according to a
statement from the Endocrine Society.

Drug companies tout testosterone as a near panacea
for such conditions. But the U.S. Food and Drug Administration (FDA)
has approved testosterone products only for hypogonadism, when the
testicles do not produce enough testosterone.

Past studies have found most U.S. men receiving testosterone therapy
don't have documented testosterone measurements, Bhasin said.

He added that testosterone sales have been growing rapidly. A market
valued between $18 and $20 million in 1988 was worth about $2.2
billion in 2013, Bhasin said.

In its statement, the Endocrine Society cautioned against widespread
use of testosterone drugs until large-scale trials can be completed.
The statement was partly a response to a decision by the FDA to
investigate the risk of stroke, heart attack and death in men taking
prescription testosterone (see Reuters story of Jan. 31, 2014,
here: http://reut.rs/MGNnYF).

Bhasin noted that estrogen generated similar hype until results from
the Women's Health Initiative published in the early 2000s sounded
alarms about potential risks. After the results of that study,
estrogen prescriptions dropped off enormously among women, he said.

"Until more information on the risks of testosterone becomes
available, older men who have pre-existing heart disease should be
particularly careful about testosterone," Bhasin said.

In January, findings from a PLOS ONE study of more than 55,000 men
suggested those with a history of heart disease roughly double their
heart attack risk in the first 90 days on testosterone therapy.
Another study looking at male patients from the Veteran Affairs
system linked testosterone to an increased risk of death, heart
attack or stroke (see Reuters Health story of Nov. 5, 2013, here:
http://reut.rs/OamNYN).

In 2010, the National Institute on Aging (NIA) halted a
testosterone trial after more cardiovascular-related problems were
reported in the testosterone group.

The NIA has another ongoing low testosterone trial that includes
about 800 men.

Men with hypogonadism who have been on stable testosterone therapy
should not stop their medication without consulting their doctor,
Bhasin said.

But for other men, it's important to remember that "low T is not
a condition, it is a number — and a number is not a disease," he
said.

"Patients need to be informed about both what is known and what is
not known about the risks and benefits of testosterone therapy
before making a personal decision about such therapy," Dr. Robert
Hoover wrote in an email to Reuters Health.

Hoover, from the National Cancer Institute in Bethesda, Maryland,
was a co-author of the PLOS ONE study.

"Until all of the major benefits and risks of testosterone therapy
are established by randomized trials and other studies, caution
should be exercised in treatment decisions, particularly among men
with existing heart disease and among older men, among whom
undiagnosed heart disease is common," Hoover wrote.